| This paper describes some basic theories of wind turbine, and basic issues of airfoils and wind turbine which include the geometric parameters, aerodynamic parameters and so on, and also introduces the mathematical and physical foundations and numerical stimulating methods of wind turbine blade. Through analyzing work principle of the wind turbine, a new technique is proposed which uses a method of jet at the blade-tip of wind turbine to enhance the efficiency of wind turbine. The 3-D numerical stimulations of the wind turbine is completed in this paper whose blade uses NACA4424 airfoil as baseline airfoil, then the original blade, the blade of jet at its trailing edge, the blade of jet at its suction surface at the blade-tip, and the blade of jet at its pressure surface are stimulated numerically by the software FLUENT. The calculating results indicate that the shapes of the jet nozzle have the important effects on the aerodynamic performances of the wind turbine: As the jet nozzle is of the equal sectional area, the output power of all wind turbines with variable jet arrangements generally is lower than of the wind turbine with the original blade no matter how many its pitching angles are; but as the jet nozzle is contracted, the calculating results of its performances are significantly improved, and its output power will be enhanced by 10.4% at the pitching angle is 8°. And jet at the pressure surface of blades is more suitable to bigger pitching angles; the results of the jet at trailing edge of the blade is better than at the suction surface on the whole, but if the position of jet at suction surface, area of spout and jet direction are suitable, the results of jet at the suction surface will be better than the jet at the trailing edge. In general, the jet technique at the blade-tip is a promising in the future, which can increase the power of wind turbine greatly, but it still needs to do further investigations to optimize variable parameters.
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